struts2 hibernate分页.doc

1). 针对网上一些 struts2分页的例子 不完整 ，代码混乱繁琐 ，我特意写了一个分页的小例子，供大家参考，如果程序有什么纰漏， 请指出。
开发环境：
eclipse3.2 + myeclipse5.5
mysql5.0
tomcat5.5
Dreamweaver2004
2)建库，并导入脚本
这里给大家介绍一个mysql客户端工具 -- SQLyog ，非常好用。
----------------------------------------------------admin.sql--------------------------------------------------
/*
SQLyog Community Edition- MySQL GUI v6.12
MySQL - 5.0.37-community-nt : Database - test
把这段脚本导入到mysql的test库里面（你可以先建一个test库 ，这样会省去很多麻烦） 
*********************************************************************
*/

/*!40101 SET NAMES utf8 */;
/*!40101 SET SQL_MODE=''*/;
create database if not exists `test`;
USE `test`;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*Table structure for table `admin` */
DROP TABLE IF EXISTS `admin`;
CREATE TABLE `admin` (
`id` int(11) NOT NULL auto_increment,
`user` char(20) default NULL,
`pass` char(20) default NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312;
/*Data for the table `admin` */
insert into `admin`(`id`,`user`,`pass`) values (786432,'天使','#####'),(786433,'天使','#####'),(786434,'天使','#####'),(786435,'天使','#####'),(786436,'天使','#####'),(819200,'天使','#####'),(819201,'天使','#####'),(819202,'天使','#####'),(819203,'天使','#####'),(819204,'天使','#####'),(819205,'wangbacheng','#####'),(851968,'天使','#####'),(851969,'天使','#####'),(851970,'天使','#####'),(851971,'天使','#####'),(851972,'天使','#####');
/*!40101 SET SQL_MODE=@OLD_SQL_MO */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
DE

3）建立数据库连接程序 ，也就是hibernate相关程序，都可以用eclipse自动生成，这个不用多说
在eclipse 中只要引入 hibernate核心包和struts2 包 就可以了

-------------------------------------------------HibernateSessionFactory.java-------------------------------------
package action;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
/**
* Configures and provides access to Hibernate sessions, tied to the
* current thread of execution. Follows the Thread Local Session
* pattern, see {@link http://hibernate.org/42.html }.
*/
public class HibernateSessionFactory {
    /** 
     * Location of hibernate.cfg.xml file.
     * Location should be on the classpath as Hibernate uses 
     * #resourceAsStream style lookup for its configuration file. 
     * The default classpath location of the hibernate config file is 
     * in the default package. Use #setConfigFile() to update 
     * the location of the configuration file for the current session.   
     */
    private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
    private static Configuration configuration = new Configuration();
    private static org.hibernate.SessionFactory sessionFactory;
    private static String configFile = CONFIG_FILE_LOCATION;
static {
    try {
    configuration.configure(configFile);
    sessionFactory = configuration.buildSessionFactory();
   } catch (Exception e) {
    System.err
      .println("%%%% Error Creating SessionFactory %%%%");
    e.printStackTrace();
   }
    }
    private HibernateSessionFactory() {
    }

/**
     * Returns the ThreadLocal Session instance. Lazy initialize
     * the <code>SessionFactory</code> if needed.
     *
     * @return Session
     * @throws HibernateException
     */
    public static Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
   if (session == null || !session.isOpen()) {
    if (sessionFactory == null) {
     rebuildSessionFactory();
    }
    session = (sessionFactory != null) ? sessionFactory.openSession()
      : null;
    threadLocal.set(session);
   }
        return session;
    }
/**
     * Rebuild hibernate session factory
     *
     */
public static void rebuildSessionFactory() {
   try {
    configuration.configure(configFile);
    sessionFactory = configuration.buildSessionFactory();
   } catch (Exception e) {
    System.err
      .println("%%%% Error Creating SessionFactory %%%%");
    e.printStackTrace();
   }
}
/**
     * Close the single hibernate session instance.
     *
     * @throws HibernateException
     */
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);
        if (session != null) {
            session.close();
        }
    }
/**
     * return session factory
     *
     */
public static org.hibernate.SessionFactory getSessionFactory() {
   return sessionFactory;
}
/**
     * return session factory
     *
     * session factory will be rebuilded in the next call
     */
public static void setConfigFile(String configFile) {
   HibernateSessionFactory.configFile = configFile;
   sessionFactory = null;
}
/**
     * return hibernate configuration
     *
     */
public static Configuration getConfiguration() {
   return configuration;
}
}
--------------------------------------------------Admin.java--------------------------------------------------
package action;

/**
* Admin generated by MyEclipse Persistence Tools
*/
public class Admin implements java.io.Serializable {

    // Fields   
     private Integer id;
     private String user;
     private String pass;

    // Constructors
    /** default constructor */
    public Admin() {
    }
/** minimal constructor */
    public Admin(Integer id) {
        this.id = id;
    }

    /** full constructor */
    public Admin(Integer id, String user, String pass) {
        this.id = id;
        this.user = user;
        this.pass = pass;
    }

    // Property accessors
    public Integer getId() {
        return this.id;
    }

    public void setId(Integer id) {
        this.id = id;
    }
    public String getUser() {
        return this.user;
    }

    public void setUser(String user) {
        this.user = user;
    }
    public String getPass() {
        return this.pass;
    }

    public void setPass(String pass) {
        this.pass = pass;
    }

}
-------------------------------------------------------------Admin.xml------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="action.Admin" table="admin" catalog="test">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="assigned" />
        </id>
        <property name="user" type="java.lang.String">
            <column name="user" length="20" />
        </property>
        <property name="pass" type="java.lang.String">
            <column name="pass" length="20" />
        </property>
    </class>
</hibernate-mapping>
-------------------------------------------------hibernate.cfg.xml--------------------------------------------
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "
<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>
<session-factory>
<property name="connection.username">root</property>
<property name="connection.url">
   jdbc:mysql://localhost:3306/test
</property>
<property name="dialect">
   org.hibernate.dialect.MySQLDialect
</property>
<property name="myeclipse.connection.profile">Mysql</property>
<property name="connection.password">root</property>
<property name="connection.driver_class">
   com.mysql.jdbc.Driver
</property>
<mapping resource="action/Admin.hbm.xml" />
</session-factory>
</hibernate-configuration>
4).建个工具类，把一些方法封装到里面
--------------------------------------------------PagerHelper.java--------------------------------------------
package action;
import java.util.Collection;
import java.util.Iterator;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
/**
* 
* @author like_dark
* 注意：java包命名的时候不能以 ”java“命名，例如 java.my.xxx ; 真是奇怪啊
*
*/
public class PagerHelper {
public Collection findWithPage(int pageSize, int startRow) throws
HibernateException {
   Collection admins = null;
   Transaction tx = null;
   try {
    Session session = HibernateSessionFactory.getSession();
    tx =   session.beginTransaction() ;
    Query q = session.createQuery("from Admin");

    q.setMaxResults(pageSize);
    q.setFirstResult(startRow);
    admins = q.list();
    mit();
   } catch (HibernateException he) {
    if (tx != null) {
     tx.rollback();
    }
    throw he;
   } finally {
    HibernateSessionFactory.closeSession();
   }
   return admins;
}
public int getRows(String query) throws
HibernateException {
   //query : select count(*) from Admin
   int totalRows = 0;
   Transaction tx = null;
   try {
    Session session = HibernateSessionFactory.getSession();
    tx = session.beginTransaction();
    totalRows = ((Long) session.createQuery(query).list().iterator().next()).intValue() ;
    mit();
   } catch (HibernateException he) {
    if (tx != null) {
     tx.rollback();
    }
    throw he;
   } finally {
    HibernateSessionFactory.closeSession();
   }
   return totalRows;
}
public static void main(String[] args) {
PagerHelper ph = new PagerHelper() ;
System.out.println("rows:"+ph.getRows("select count(*) from Admin")) ;
}
}
5) .struts2相关程序和配置
--------------------------------------------------struts.xml----------------------------------------
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="default" namespace="/" extends="struts-default">
   <action name="pager" class="action.PageAction">
    <result name="success">
     /index.jsp
    </result>
    <result name="fail">
     /index.jsp
    </result>
   </action>
</package>
</struts>
----------------------------- PageAction.java ----------------------
package action;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class PageAction extends ActionSupport {

private int totalRows; //总行数
private int pageSize = Constants.PAGE_SIZE; //每页显示的行数
private int currentPage; //当前页号
private int totalPages; //总页数
private boolean hasNext ; //是否有下一页
private boolean hasPrevious ; //是否有上一页
private Collection CurrentList; //当前数据集
private Collection indexList ; //页码集合
public Collection getCurrentList() {
   return CurrentList;
}
public void setCurrentList(Collection currentList) {
   CurrentList = currentList;
}
/**
* 这里最好用一个引用参数化
*/
public Collection getIndexList() {

   ArrayList result = new ArrayList();
   for(int i = 1;i<=getTotalPages();i++){   
            result.add(new Integer(i));
   }
      return result ; 
}
public void setIndexList(Collection indexList) {
   this.indexList = indexList;
}
public String execute() throws Exception {
   int totalRows = 0 ;

   try{
    PagerHelper ph = new PagerHelper() ;
    totalRows =   ph.getRows("select count(*) from Admin") ;    //总行数
    totalPages = (totalRows + pageSize - 1) /pageSize; //总页数
    setIndexList(getIndexList()) ; //生成页码集合

    if (currentPage==0 || currentPage<1) {
     first();
    }
            if(currentPage > totalPages){
            last();
            }
            if(currentPage >= 1 && currentPage < totalPages){
            hasNext = true ;
            }
            if(currentPage > 1 && currentPage <= totalPages){
            hasPrevious = true ;
            }

/**
* 为了利用session 可以实现SessionAware接口 然后重载 void setSession(Map session) 方法
* action implementation SessionAware{ 
*      private Map session ;
*      void setSession(Map session){
*         this.session = session ;
*      } 
*      session.put(...); session.get(..)
*      或者 继承import com.opensymphony.xwork2.ActionContext;
*      ActionContext ctx = ActionContext.getContext();
    Map session = ctx.getSession() ;
*/ 
            CurrentList = ph.findWithPage(Constants.PAGE_SIZE, getStartRow()) ;
    return SUCCESS ;
   }catch(Exception e){
    e.printStackTrace() ;
    return ERROR ;
   }
}
public int getCurrentPage() {
   return currentPage;
}
public void setCurrentPage(int currentPage) {
   this.currentPage = currentPage;
}
public int getPageSize() {
   return pageSize;
}
public void setPageSize(int pageSize) {
   this.pageSize = pageSize;
}
public int getStartRow() {
   if(getCurrentPage() == 1)
    return 0;
   else
      return (getCurrentPage()-1) * pageSize; 
}

public int getTotalPages() {
   return totalPages;
}
public void setTotalPages(int totalPages) {
   this.totalPages = totalPages;
}
public int getTotalRows() {
   return totalRows;
}
public void setTotalRows(int totalRows) {
   this.totalRows = totalRows;
}
public void first() { //首页
   currentPage = 1;

}
/*public void previous() { //上一页
   if (currentPage == 1) {
    return;
   }
   currentPage--;
}
public void next() {   //下一页
   if (currentPage < totalPages) {
    currentPage++;
   }
}*/
public void last() { //尾页
   currentPage = totalPages;
}
public boolean isHasNext() {
   return hasNext;
}
public void setHasNext(boolean hasNext) {
   this.hasNext = hasNext;
}
public boolean isHasPrevious() {
   return hasPrevious;
}
public void setHasPrevious(boolean hasPrevious) {
   this.hasPrevious = hasPrevious;
}

}
----------------------------struts.properties------------------------------
#struts.custom.i18n.resources=globalMessages
struts.action.extension=do

5) web相关配置和程序
--------------------- web.xml -----------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="2.4" xmlns=" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" 
    <display-name>Struts Blank</display-name>
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    <